A need has existed for an extended period of time, in the armed services and industry, for an oscillator having the ability to generate an RF signal from a D.C. power source which has the capability of rapidly selecting different RF output frequencies. This need is particularly acute in applications by frequency agile sources used in electronic warfare and communication links. Commercial applications for the invention will include the use in transmitters and receivers using phased-locked loops to stabilize a desired frequency. Prior art devices did not provide a reliable method to control a wide range of frequencies without concern for “burning out” or the need for shielding of the ferroelectric frequency control material when used in pulsed systems with high power or in environments where the generating sources are unstable. Prior art devices using a varactor diode as a variable capacitance for voltage controlled oscillators also were unreliable in high power pulsed systems. The varactor diode was vulnerable under the aforementioned environment whenever the maximum current rating was exceeded.